thumbnails: generate/load thumbnails on visible items only, and drop

background loading.

Views load much more quickly when delaying any thumbnail processing
until all items are fully loaded.

An attempt is made to load 'ahead' and 'behind' the visible range,
but in the list view, the current api does not allow scanning for
rows 'above' the current view position, only below.  As a result,
scrolling a view down in the list view will reveal icons that have
already been queued to load their thumbnail, but scrolling up will
not.  This behavior works properly in the icon views in both
directions.

Author: mtwebster

libnemo-private/nemo-directory-async.c

@@ -1645,7 +1645,7 @@ lacks_btime (NemoFile *file)
 static gboolean
 lacks_filesystem_info (NemoFile *file)
 {
-	return !file->details->filesystem_info_is_up_to_date;
+	return nemo_file_is_directory (file) && !file->details->filesystem_info_is_up_to_date;
 }
 
 static gboolean
@@ -1692,7 +1692,8 @@ lacks_extension_info (NemoFile *file)
 static gboolean
 lacks_thumbnail (NemoFile *file)
 {
-	return nemo_file_should_show_thumbnail (file) &&
+	return file->details->load_thumb &&
+        nemo_file_should_show_thumbnail (file) &&
 		file->details->thumbnail_path != NULL &&
 		!file->details->thumbnail_is_up_to_date;
 }

libnemo-private/nemo-file-private.h

@@ -56,6 +56,8 @@ struct NemoFileDetails
 
 	eel_ref_str name;
 
+    gchar *cached_uri;
+
 	/* File info: */
 	GFileType type;
 
@@ -221,7 +223,8 @@ struct NemoFileDetails
 
 	eel_boolean_bit filesystem_readonly           : 1;
 	eel_boolean_bit filesystem_use_preview        : 2; /* GFilesystemPreviewType */
-	eel_boolean_bit filesystem_info_is_up_to_date : 1;
+    eel_boolean_bit filesystem_info_is_up_to_date : 1;
+	eel_boolean_bit load_thumb                    : 1;
 
     NemoFilePinning pinning;
 

libnemo-private/nemo-file.c

@@ -501,6 +501,7 @@ nemo_file_clear_info (NemoFile *file)
 	file->details->ctime = 0;
     file->details->btime = 0;
 	file->details->trash_time = 0;
+    file->details->load_thumb = FALSE;
 	g_free (file->details->symlink_name);
 	file->details->symlink_name = NULL;
 	eel_ref_str_unref (file->details->mime_type);
@@ -564,7 +565,7 @@ nemo_file_new_from_filename (NemoDirectory *directory,
 	file->details->name = eel_ref_str_new (filename);
 
 #ifdef NEMO_FILE_DEBUG_REF
-	DEBUG_REF_PRINTF("%10p ref'd", file);
+	DEBUG_REF_PRINTF("%10p ref'd\n", file);
 #endif
 
 	return file;
@@ -676,7 +677,7 @@ nemo_file_new_from_info (NemoDirectory *directory,
 	update_info_and_name (file, info);
 
 #ifdef NEMO_FILE_DEBUG_REF
-	DEBUG_REF_PRINTF("%10p ref'd", file);
+	DEBUG_REF_PRINTF("%10p ref'd\n", file);
 #endif
 
 	return file;
@@ -865,6 +866,8 @@ finalize (GObject *object)
 		metadata_hash_free (file->details->metadata);
 	}
 
+    g_free (file->details->cached_uri);
+
 	G_OBJECT_CLASS (nemo_file_parent_class)->finalize (object);
 }
 
@@ -877,7 +880,7 @@ nemo_file_ref (NemoFile *file)
 	g_return_val_if_fail (NEMO_IS_FILE (file), NULL);
 
 #ifdef NEMO_FILE_DEBUG_REF
-	DEBUG_REF_PRINTF("%10p ref'd", file);
+	DEBUG_REF_PRINTF("%10p ref'd\n", file);
 #endif
 
 	return g_object_ref (file);
@@ -893,7 +896,7 @@ nemo_file_unref (NemoFile *file)
 	g_return_if_fail (NEMO_IS_FILE (file));
 
 #ifdef NEMO_FILE_DEBUG_REF
-	DEBUG_REF_PRINTF("%10p unref'd", file);
+	DEBUG_REF_PRINTF("%10p unref'd\n", file);
 #endif
 
 	g_object_unref (file);
@@ -1639,6 +1642,18 @@ nemo_file_get_uri (NemoFile *file)
 	return uri;
 }
 
+const char *
+nemo_file_peek_uri (NemoFile *file)
+{
+    g_return_val_if_fail (NEMO_IS_FILE (file), NULL);
+
+    if (file->details->cached_uri == NULL) {
+        file->details->cached_uri = nemo_file_get_uri (file);
+    }
+
+    return file->details->cached_uri;
+}
+
 /* Return the actual path associated with the passed-in file. */
 char *
 nemo_file_get_path (NemoFile *file)
@@ -4342,6 +4357,12 @@ nemo_file_delete_thumbnail (NemoFile *file)
     }
 }
 
+gboolean
+nemo_file_has_loaded_thumbnail (NemoFile *file)
+{
+    return file->details->thumbnail_is_up_to_date;
+}
+
 static void
 prepend_icon_name (const char *name,
 		   GThemedIcon *icon)
@@ -4636,7 +4657,7 @@ nemo_file_get_icon (NemoFile *file,
 	DEBUG ("Called file_get_icon(), at size %d, force thumbnail %d", size,
 	       flags & NEMO_FILE_ICON_FLAGS_FORCE_THUMBNAIL_SIZE);
 
-	if (flags & NEMO_FILE_ICON_FLAGS_USE_THUMBNAILS &&
+	if ((flags & NEMO_FILE_ICON_FLAGS_USE_THUMBNAILS) &&
 	    nemo_file_should_show_thumbnail (file)) {
 
         if (flags & NEMO_FILE_ICON_FLAGS_FORCE_THUMBNAIL_SIZE) {
@@ -4727,12 +4748,12 @@ nemo_file_get_icon (NemoFile *file,
 			   !file->details->is_thumbnailing &&
 			   !file->details->thumbnailing_failed) {
 			if (nemo_can_thumbnail (file)) {
-				nemo_create_thumbnail (file, get_throttle_count (file));
+				nemo_create_thumbnail (file, get_throttle_count (file), TRUE);
 			}
 		}
 	}
 
-	if (file->details->is_thumbnailing &&
+	if (file->details->thumbnail_path == NULL && nemo_can_thumbnail (file) &&
 	    flags & NEMO_FILE_ICON_FLAGS_USE_THUMBNAILS)
 		gicon = g_themed_icon_new (ICON_NAME_THUMBNAIL_LOADING);
 	else
@@ -8019,6 +8040,13 @@ nemo_file_invalidate_extension_info_internal (NemoFile *file)
 		nemo_module_get_extensions_for_type (NEMO_TYPE_INFO_PROVIDER);
 }
 
+void
+nemo_file_set_load_thumb (NemoFile *file,
+                          gboolean  load_thumb)
+{
+    file->details->load_thumb = load_thumb;
+}
+
 void
 nemo_file_invalidate_attributes_internal (NemoFile *file,
 					      NemoFileAttributes file_attributes)

libnemo-private/nemo-file.h

@@ -189,6 +189,7 @@ const char *            nemo_file_peek_name                         (NemoFile
 GFile *                 nemo_file_get_location                      (NemoFile                   *file);
 char *			 nemo_file_get_description			 (NemoFile			 *file);
 char *                  nemo_file_get_uri                           (NemoFile                   *file);
+const char *            nemo_file_peek_uri                          (NemoFile                   *file);
 char *                  nemo_file_get_path                          (NemoFile                   *file);
 char *                  nemo_file_get_uri_scheme                    (NemoFile                   *file);
 NemoFile *          nemo_file_get_parent                        (NemoFile                   *file);
@@ -240,6 +241,7 @@ NemoRequestStatus   nemo_file_get_deep_counts                   (NemoFile
 									 gboolean                        force);
 gboolean                nemo_file_should_show_thumbnail             (NemoFile                   *file);
 void                    nemo_file_delete_thumbnail                  (NemoFile                   *file);
+gboolean                nemo_file_has_loaded_thumbnail              (NemoFile                   *file);
 gboolean                nemo_file_should_show_directory_item_count  (NemoFile                   *file);
 gboolean                nemo_file_should_show_type                  (NemoFile                   *file);
 GList *                 nemo_file_get_keywords                      (NemoFile                   *file);
@@ -521,7 +523,7 @@ void     nemo_file_set_is_desktop_orphan          (NemoFile *file, gboolean is_d
 
 gboolean nemo_file_get_pinning                    (NemoFile *file);
 void     nemo_file_set_pinning                    (NemoFile *file, gboolean  pin);
-
+void nemo_file_set_load_thumb                     (NemoFile *file, gboolean load_thumb);
 /* Debugging */
 void                    nemo_file_dump                              (NemoFile                   *file);